package chap4;
public class ParamTest {
    public static void main(String[] args){

        /* 
         * Test1: Methods can't modify numeric parameters   
         */
        System.out.println("Testing tripleValue: ");
        double percent = 10;
        System.out.println("Before: percent = " + percent);
        tripleValue(percent);
        System.out.println("After: percent = " + percent);

        /*
         * Test2: Methods can change the state of object parameters
         */
        System.out.println("\nTesting tripleSalary:");
        Employee harry = new Employee("Harry", 50000);
        System.out.println("Before: salary = " + harry.getSalary());
        tripleSalary(harry);
        System.out.println("After: salary = " + harry.getSalary());

        /*
         * Test3: Methods can't attach new objects to object parameters
         */ 
        System.out.println("\nTesting Swap:");
        Employee a = new Employee("Alice", 70000);
        Employee b = new Employee("Bob", 60000);
        System.out.println("Before: a = " + a.getName());
        System.out.println("Before: b = " + b.getName());
        swap(a, b);
        System.out.println("After: a = " + a.getName());
        System.out.println("After: b = " + b.getName());
    }
    
    public static void tripleValue(double x)
    {
        x = 3 * x;
        System.out.println("End of the method: x = " + x);
    }

    public static void tripleSalary(Employee x)
    {
        x.raiseSalary(200);
        System.out.println("End of the method: salary = " + x.getSalary());
    }

    public static void swap(Employee x, Employee y)
    {
        Employee temp = x;
        x = y;
        y = temp;
        System.out.println("End of method: x = " + x.getName());
        System.out.println("End of method: y = " + y.getName());
    }

}

/**
 * A test class
 */
class Employee
{
    private String name;
    private double salary;

    public Employee(String n, double s)
    {
        name = n;
        salary = s;
    }

    public String getName()
    {
        return name;
    }

    public double getSalary()
    {
        return salary;
    }
    
    /**
     * Raises the salary of an employee.
     * @param byPercent the percentage by which to raise the salary(e.g. 10 means 10%).
     */
    public void raiseSalary(double byPercent)
    {
        double raise = salary * byPercent / 100;
        salary += raise;
    }
}
